Hemp History Mankind's Use of Hemp Has a Long History with the Earliest Findings of Hemp Cultivation at a 12,000 Year Old Neolithic Site in Yuan-Shan, Taiwan
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Hemp History Mankind's use of hemp has a long history with the earliest findings of hemp cultivation at a 12,000 year old Neolithic site in Yuan-shan, Taiwan. Hemp was widely grown across Britain in the Middle Ages; Cwm Cywarch (hemp valley) found in Gwynedd and Hemel Hempstead (Hemels cannabis Farm) in Hertfordshire both named after this important agricultural crop grown predominantly for its tremendous value as a fibre for rope and textiles. During the Tudor period the British navy was so dependent on hemp for rope and canvas farmers were fined if they did not grow a hemp crop. It was once a very important crop in the USA, Henry Fords first car was made from hemp plastic and run on hemp fuel. Traditionally China is the biggest producer of hemp seeds where they have long been considered a beneficial food in TCM. Vested interest in timber, paper making, the petro chemical industry and synthetic fibres saw the end in the 20 th century of this mighty crop, however, appreciation of the sustainable nature of this plant means we are now looking at renewed hemp production. What is hemp There is often confusion between hemp and marijuana They are both cannabis and belong to the Cannabaceae family, what differentiates them from each other is the concentration of the psychoactive cannabinoid tetrahydrocannabinol, often referred to as THC Hemp has generally less that 0.3% THC too low to produce an intoxicating effect, whereas cannabis can have up to 30% If you grow for fibre you use the stalk of a particular variety and if you grow seeds for food you use a different variety. Both hemp (often referred to as industrial hemp) and cannabis can be used for medicine. Recently dual hemp varieties have been introduced that enable the harvest of both seed and fibre from the one plant. Cannabis contains many different cannabinoid compounds each strain of the plant with different varieties and strengths. Many have a medicinal effect and there is enough evidence to show that THC from cannabis can be effective in the symptomatic relief of multiple sclerosis for it to be prescribed as a medicine on the NHS. There is growing evidence it can be used as an anti-nausea drug in chemotherapy and generally relieve the pain of disease. Hemp & cannabis contain other cannabinoids the best known one is is cannabidiol (CBD ). Research has shown CBD to have analgesic, anti-inflammatory, and anti-anxiety properties without the psychoactive effects. Cannabinoids bind to special receptor sites in places like the brain, other organs and the immune system. When cannabinoids bind to these receptor sites, they have influence over some part of the function or activity of what this site controls. CBD oil can be extracted from the flower of industrial hemp grown for fibre. Three methods are used the best and safest is the C02 method but also the most expensive so the alternative ethanol method of extraction is often used. In addition extraction through a carrier oil like olive oil can be used, this is the safest method with no unwanted residues but produces the weakest medicinal oil. It has generally been considered that specific compounds in the plant have medicinal benefits but the plant itself does not have a medical value but a groundbreaking Israeli study published in 2015 has shown the whole plant extract is superior in the treatment of inflammatory conditions over a single compound. * 1 Hemp is an annual broadleaf plant with a taproot grown from seed with a diverse number of uses. Fibres can be used to make clothing, paper, composite manufacture (like car door panels), construction material, insulation and animal bedding. Oil can be extracted from the seed both for the dietary market and cosmetics and toiletries. Hemp seeds can be eaten and they are one of the most nutritious foods known to man. Special growing restrictions A home office licence is required to grow hemp in the UK. To successfully apply for a license to cultivate hemp, you must be registered as a company with Companies House, with a valid company number. Company details must be provided to the Home Office Controlled Drugs Licensing department in order to register online and complete the application. Companies must also submit a statement that clearly outlines the location, grid references, hectarage of the proposed growing site. In addition only approved cultivars may be grown in the UK. The cost to apply for a hemp cultivation license is £580, and the fee for each subsequent renewal is £326. Varieties There are different varieties of hemp, each with its own set of characteristics. Some are more suited to fibre with stalks reaching up to 5 metres and others to seeds. In recent years dual hemp varieties have been introduced in the UK these varieties tend to be short reaching just 2m and are grown primarily for grain production but the hurds can still be used in certain fibre applications such as composite manufacture, construction or animal bedding. Growing hemp Hemp is tolerant to a wide range of soils but its preference is for fairly free draining clay loam type soils with a pH of around 6 – 7 , hemp will not thrive in acid soils Hemp in the UK is sown after any risks of a hard frost have passed. It is a very fast growing plant quickly forming a leaf canopy which stops weeds competing and makes a herbicide unnecessary. Terpene in hemp repels insects so pesticides are not necessary either. As the plant grows it constantly sheds its leaves which means many nutrients have been recycled into the topsoil by harvest time. Hemp has a very long tap root able to bring up nutrients from deep in the soil. Given home office restrictions hemp is not a crop for the garden or allotment rather an agricultural crop. There are many organisations working to remove the restrictive legislation so that we can all benefit from this plant that is good for our health and the health of the planet. Harvesting Terminology Bast – long fibres Conditioning – splitting open to assist drying Decortication – removal of the tough outer layer of the stem Dehulling – removing the hard shell from the soft nut Hackling – combing out the long fibres Hurd/ Shive - inner fibrous material Retting fungal activity that begins the breakdown of the tough bonds within the stems Stooking - sheaves set upright in a field to dry Tedding - spread out and dry Hemp fibre harvesting Fiber hemp is ready to harvest about the time the plant is finished producing pollen and the first seeds start to develop. This does vary with the variety and maturity of the fiber desired. If left beyond this stage, the fiber maybe too coarse for some hemp material. There are two main methods of harvesting; binding and stooking or the more popular mowing - conditioning and baling, where the crop is cut and left to begin dew-retting then dried, baled and stored before further processing. A variety of different machinery can be used including an allen scythe, sickle bar mowers, standard mower-conditioners, modified rape swathers, and binders. Hemp seed harvesting Harvesting hemp seed can be tricky. Not only do the seeds mature at different rates on different plants, they can mature at different times on the same plant. When the lower seeds near the stalk are mature and have split open, the seeds near the top are not yet mature. The trick is to determine at what point harvesting should take place that will amount to a minimal loss of seed and this is generally in late September or early October about sixteen weeks after planting. Hemp seed is harvested with a combine tractor and, almost immediately, cleaned to remove any stocks, leaves, and immature seeds, then stored in a cool dry place. Dual purpose hemp harvesting Dual purpose hemp is harvested in a two step process. First the seed heads are cut, then the straw. A combine can be modified to perform both functions at the same time by mounting a sickle-bar mower under the header to operate close to the ground. The optimum harvest for seeds is when about 70% of the seeds are ripe but it is a balancing act as the more mature the fibres of hemp become there is a tendency to wrap tenaciously around the moving parts on the combine and cause a harvesting problem. Advancement in harvesting equipment Harvesting equipment for fibre crops have made rapid advancements over the last 20 years. Hempflax in the Netherlands have developed the Hempflax Method which is generally considered the most efficient harvester for dedicated fibre growing. In Germany, Goltz, Deutz & Bata in collaboration have developed hemp harvesters where the fibre, seed threshing and stalk chopping is completed in one pass. Recent developments in harvesting equipment have revolutionised the process but this equipment is expensive and therefore most suited to large scale production. Farmers need to be assured of the market for their crop before investing in equipment. Throughout Europe there are industrial hemp businesses who are seeking raw materials. Hempflax in the village of Oude Pekela in the Netherlands, through contract farming with farmers in the Netherlands and Germany produces environmentally friendly products. In the UK demand for hemp in the UK building industry is growing. Hemp-Lime Spray Limited promotes the use of hempcrete and provides technical support and know-how for all types of hempcrete projects, particularly hempcrete spraying. Community projects growing hemp could share equipment (though this does present the problem associated with the equipment being available at the optimum time to harvest for everyone) Harvesting for seeds is relatively easy, harvesting for fibre requires strong machinery.